Maspin is a non-inhibitory serine protease inhibitor (serpin) that was originally identified as a type II tumor suppressor protein in mammary epithelial cells (Zou et al. (1994) Science 263, 526-529; herein incorporated by reference in its entirety). One major tumor suppressor function of maspin is suppression of tumor cell motility, since it inhibits tumor cell migration/invasion in vitro and suppresses metastasis in mouse models (Zou et al. (1994) Science 263, 526-529; Abraham et al. (2003) J Urol 169, 1157-1161; Seftor et al. (1998) Cancer Res 58, 5681-5685; Shi et al. (2001) Cancer Res 61, 6945-6951; Shi et al. (2002) Mol Ther 5, 755-761; Zhang et al. (1997) Mol Med 3, 49-59; Zhang et al. (2000) Oncogene 19, 6053-6058; herein incorporated by reference in their entireties). Several studies show that pericellular maspin inhibits cell motility by enhancing cell adhesion (Abraham et al. (2003) J Urol 169, 1157-1161; Seftor et al. (1998) Cancer Res 58, 5681-5685; Ngamkitidechakul et al. (2001) Invest Ophthalmol Vis Sci 42, 3135-3141; Cella et al. (2006) Faseb J 20, 1510-1512; herein incorporated by reference in their entireties). In addition to its tumor suppressing functions, maspin is also essential for normal fetal development since maspin knockout mice are embryonic lethal during the peri-implantation stage partially due to disrupted visceral endodermal cell adhesion (Gao et al. (2004) Development 131, 1479-1489; herein incorporated by reference in its entirety).